What is Molecular Biology?


1.What is Molecular Biology?

Molecular Biology is a branch of biology that studies the molecular basis of biological activity in and between cells. Biomolecular synthesis, modification, mechanisms, and interactions are all covered. Molecular biology is the study of the chemical and physical structure of biological macromolecules.

Molecular biology was initially defined as an approach focused on the underpinnings of biological phenomena - discovering the structures of biological molecules as well as their interactions, and how these interactions explain classical biology observations.

Because living things, like non-living things, are made of chemicals, a molecular biologist studies how molecules interact with one another in living organisms to perform life functions.

2.Molecular Biolog's History

It became evident that both of these scientific fields attempted to understand the molecular mechanisms behind critical cellular activities as they developed in the 20th century. The creation and improvement of new technologies have been closely correlated with developments in molecular biology. Understanding these researchers and their experiments is essential to comprehending the history of molecular biology, which has been clarified by the efforts of many scientists.

The identification of DNA's structural makeup was a significant turning point in molecular biology. This work was started in 1869 by the Swiss biologist Friedrich Miescher, who initially hypothesized the nuclein structure, which is now recognized as DNA or deoxyribonucleic acid. By examining the components of pus-filled bandages and noting the distinctive characteristics of the "phosphorus-containing compounds," he was able to identify this unusual material.

Phoebus Levene, who suggested the "polynucleotide model" of DNA in 1919 as a result of his biochemical investigations on yeast, was another significant contributor to the DNA model. Erwin Chargaff built on Levene's research and identified a few crucial characteristics of nucleic acids in 1950. The first is that the sequence of nucleic acids differs between species. Second, the overall concentration of pyrimidines and purines (adenine and guanine) is always the same (cysteine and thymine).Today, this is referred to as Chargaff's rule. James Watson and Francis Crick used the X-ray crystallography work done by Rosalind Franklin and Maurice Wilkins to disclose the double helical helix of DNA in 1953. In their description of the DNA structure, Watson and Crick speculated about the implications of this particular structure for potential DNA replication mechanisms.


3.What Are the Differences Between Molecular Biology, Biochemistry, and Genetics?

We mentioned earlier that molecular biology is related to other fields, but that doesn't mean they're identical. When comparing molecular biology, biochemistry, and genetics, the main thing they all have in common is that they all study organisms at the molecular level.

Nonetheless, each discipline is applied differently and focuses on different areas.


Biochemistry vs. Molecular Biology

Scientists and researchers in biochemistry pay more attention to molecules than to other proteins. Biochemistry is also more concerned with nucleic acids and the chemical reactions that occur when different compounds interact.

One of the most significant differences is that biochemistry methodology relies heavily on organic chemistry when compared to molecular biology, so the way experiments are carried out differs.

Genetics vs. Molecular Biology

Genetics research and experiments are conducted on a much larger scale than molecular biology. This is because geneticists are interested in how genetic codes change or affect different organisms, as well as heritable traits. Heritability implies that studies are carried out by examining large segments of the population.

In contrast to molecular biology, which studies molecules, genetics studies large groups of people to reach its conclusions.


4.molecular biology methods

Molecular cloning-Transmission picture

A DNA sequence of interest is isolated through molecular cloning, which is then transferred into a plasmid vector.

In the 1960s, recombinant DNA technology was first created. Using the polymerase chain reaction (PCR) and/or restriction enzymes, a DNA sequence encoding a protein of interest is cloned onto a plasmid (expression vector). A multiple cloning site (MCS), a selection marker, and an origin of replication are often the plasmid vector's three most distinguishing characteristics (usually antibiotic resistance).

The promoter regions and transcription start site, which control the production of cloned genes, are also located upstream of the MCS.

Chain reaction with polymerase

The Polymerase Chain Reaction (PCR) is a very flexible method for replicating DNA. In a nutshell, PCR enables the predetermined copying or modification of a certain DNA sequence. Under ideal circumstances, the reaction, which has a tremendous amount of power, could multiply one DNA molecule into 1.07 billion molecules in less than two hours.

The study of gene expression, the identification of dangerous bacteria, the detection of genetic mutations, and the introduction of changes to DNA are just a few of the many uses for PCR. The PCR method can be used to alter specific DNA bases, a process known as site-directed mutagenesis, or to add restriction enzyme sites to the ends of DNA molecules.

Additionally, PCR can be used to find out if a certain DNA fragment is present in a cDNA library. Reverse transcription PCR (RT-PCR) amplifies RNA, while quantitative PCR, developed more subsequently, allows for the quantitative measurement of DNA or RNA molecules.


Electrophoresis of gel

By separating molecules according to their size, gel electrophoresis uses an agarose or polyacrylamide gel as a medium.

One of the main instruments in molecular biology is this method.Because the DNA backbone contains negatively charged phosphate groups, the DNA will migrate through the agarose gel towards the positive end of the current, which is the underlying idea behind how DNA fragments can be separated.Using an SDS-PAGE gel or a procedure known as 2D gel electrophoresis, proteins can also be sorted according to their size and electric charge.


Using a Bradford assay

The Bradford Assay is a molecular biology method that makes use of the special characteristics of a dye called Coomassie Brilliant Blue G-250 to quickly and accurately quantify protein molecules.

When Coomassie Blue binds to protein, it changes color noticeably from reddish-brown to vivid blue.Coomassie Blue emits a reddish-brown color and has a background wavelength of 465 nm in its unstable, cationic state. Coomassie Blue emits a vivid blue color and adjusts its background wavelength to 595 nm when it binds to protein in an acidic solution.It is advised to collect absorbance values between 5 and 20 minutes after the reaction starts because proteins in the test bind Coomassie blue in about 2 minutes, and the protein-dye combination is stable for roughly an hour. The Bradford test does not require a lot of equipment because the protein concentration can be determined using a visible light spectrophotometer.



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